When cutting through wood, particularly large size timbers and trees, the kerf produced by the cutting implement as the cut is produced due to improper balancing of the material being cut, or in the case of live trees, as it is not always possible to properly brace the tree for the cutting. When such binding of the cutting blade by the kerf occurs, it becomes impossible to continue to use the implement until the material being cut is moved so that the kerf will open up again.
The simplest device for preventing kerf from binding the cutting blade is to use a wedge above the cutting blade. However, in many instances, this is not always possible because the thickness of the material being cut may be such that the wedge cannot be inserted above the cutting blade before binding in the kerf occurs. U.S. Pat. No. 3,042,088 discloses the use of a device mounted on the housing of a chain saw which has a bevelled wheel operating on a slidable bar which in turn is pivotally mounted to the housing to spread the kerf. This device would appear suitable providing that the kerf spreader can be inserted into the kerf before the actual binding of the chain saw blade bar occurs. In many instances in cutting small diameter trees and limbs, the binding can occur before the kerf is the depth of the chain saw blade bar. Also, this type of device would not appear to be useable with any other woodcutting implement but a chain saw.